The first time one of these companies hire someone from Iran, Syria, North Korea, Cuba or any of the other countries under sanctions practically everywhere and et hit by multi-million dollar penalties and severe restrictions on how they can operate in the future, this thing will stop being a thing.
How would they even know, if a competitor got hired to work for them?
This might possibly be a good thing for workers, but there's so much risk involved for the employer, any competent legal expert would strongly advice against it.